Vacuum cleaners are commonly used in households for removing dust and debris from various surfaces, and today it is essential that the vacuum cleaner be easy to use, easy to clean and versatile in respect of fields of application.
Generally, a vacuum cleaner has a filter for removing dust from dust laden air flowing through the vacuum cleaner. After some time of usage dust adheres to the filter surface which leads to a pressure drop and reduced vacuum cleaning efficiency. Thus, cleaning of the filter is necessary to remove the particulate matter, such as dust, hair and fibers, from the filter.
In case of a clogged filter, it is also common to replace the filter with a new one for regaining vacuum cleaning efficiency. WO 2004/069021 discloses a hand held vacuum cleaner having housing incorporating a motor fan unit. A dust container is connected to the housing, and when the vacuum cleaner is operated, dust laden air flows through an inlet, into the dust container, through a filter for trapping dust, and thereafter past the motor fan unit and out through air outlets. After operation, fine dust is clogged-to the filter, and sucked up debris is trapped in the dust container.
The dust container is emptied by letting out trapped debris through a dust outlet opening. Another way of emptying the dust container involves removing the dust container, removing the filter from the dust container and letting out debris through a hole previously covered by the removed filter. The filter is cleaned by manually shaking or brushing the filter, or by vacuum cleaning the filter with another vacuum cleaner.
The filter cleaning process for the described vacuum cleaner is rather cumbersome. Moreover, dust removed from the filter is often uncontrollably spread to the surroundings.